1. Field of the Invention
The present invention relates to a video transfer system that reproduces the video image data recorded on the recording medium and transfers it to an external apparatus, and a video transmitting apparatus and a video receiving apparatus that make up the video transfer system.
2. Related Background Art
The HDV specifications (Specifications of HDV Recording Format Version 1.0 September 2003) for recording the MPEG2 coded data on the magnetic tape on which the video image data conforming to a DV (Digital Video) method is recorded, were settled by an HD Digital VCR Conference. The HDV specifications are specifications for recording the HD (High Definition) video image data. Such a technology for recording the HD video image data was also offered by Japanese Patent Application Laid-Open No. 2001-275076, for example.
A so-called nonlinear editing system of connecting a player that reproduces the video image data recorded on the magnetic tape to a personal computer (hereafter referred to as a PC), transferring the video image data, and capturing and editing the video image data on the PC has been generally employed.
By the way, there may happen that a scene is not correctly reproduced due to blinding of a reproducing head or instantaneous bad contact of the head, when the magnetic tape is reproduced by the player. Or there is possibility that the scene may not be reproduced correctly, because part of the recorded data is broken, or the recording medium is damaged. Such a situation is a trouble that may occur in the disk, as well as the magnetic tape.
As a cause of such trouble, a reproduction error occurs in the player, if the error correcting process becomes imperfect due to large dropout or erroneous reproduced data. If this reproduction error occurs during reproduction of the video image data compressed by an MPEG compression method, the following problems arise.
That is, the MPEG compression method employed for the HDV specifications is a technology that enables high compression by using the bidirectional prediction between pictures. Specifically, in an encoding unit named a Group of Picture (hereafter referred to as a GOP), a single intraframe coded image called an I frame is included and the remaining images are composed of the interframe coded image called a P frame or a B frame to be decoded by referring to the I frame. When the reproduction error occurs momentarily at the timing of I frame, for example, all the image of oneGOP becomes to be of reproduction error because the I frame drops out, even if the error is resolved immediately soon. Since oneGOP is usually 15 frames, if the error occurs in the I frame, the video is not outputted for a period of about 0.5 seconds, or the freeze-video not updated from the previous scene is outputted.
And since in a state of reproduction error, the video image data is not outputted to the outside, or the freeze-video image or degraded video is outputted to the outside, the PC connected to the player ceases to receive, or receives the video image data of poor quality, whereby the reproduction error only obstructs the viewing or editing because its cause is not known on the PC side.